Oven for heating food

ABSTRACT

An oven for heating food is disclosed. The oven has at least one heating compartment with a left side wall, a right side wall, a back wall, a top wall, a bottom wall, and an open front, without a door, in open communication with a surrounding environment outside the oven. Gas flow openings are provided in the left and right side walls. The oven includes a blower for blowing gas through the gas flow openings into the heating compartment, and a heater for heating gas blowing into the heating compartment through the openings. In certain embodiments, the gas flow openings are configured such that substantially all of the gas blowing into the heating compartment is directed generally away from the open front of the compartment.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation application claiming priority to PCTApplication No. PCT/US2011/028786 filed Mar. 17, 2011, the entirety ofwhich is hereby incorporated by reference.

FIELD OF THE INVENTION

The present invention generally relates to food serving equipment, andmore particularly to an oven for heating food.

BACKGROUND OF THE INVENTION

In one embodiment, this invention is directed to an oven which uses hotgas to maintain pre-cooked food at proper temperatures before serving.This type of equipment is often referred to using such terms as aholding oven, or a holding unit, or a food warmer. Such equipment isused in the fast food service industry to heat food prior to serving it.

SUMMARY OF THE INVENTION

In one embodiment, this invention is directed to an oven for heatingfood, comprising a housing having a left side, a right side, a top, abottom, a back, and a front. The housing defines an oven cavitycomprising at least one heating compartment for heating food placed inthe compartment. The heating compartment has a left side wall, a rightside wall, a back wall, a top wall, a bottom wall, and an open front,without a door, in open communication with a surrounding environmentoutside the oven. Gas flow openings are provided in the left and rightside walls. The oven includes a blower for blowing gas through the gasflow openings into the heating compartment, and a heater for heating gasblowing into the heating compartment through the openings. The gas flowopenings are configured such that substantially all of the gas blowinginto the heating compartment is directed generally away from the openfront of the compartment.

In another embodiment, this invention is directed to an oven for heatingfood, comprising a housing having a left side, a right side, a top, abottom, a back, and a front. The housing defines an oven cavitycomprising at least one heating compartment for heating food placed inthe compartment. The heating compartment has a left side wall, a rightside wall, a back wall, a top wall, a bottom wall, and an open front,without a door, in open communication with a surrounding environmentoutside the oven. Gas flow openings are provided in the left and rightside walls. The oven includes a blower for blowing gas through the gasflow openings into the heating compartment, and a heater for heating gasblowing into the heating compartment through the openings. A movable airdeflector at the top of the open front of the heating compartment isprovided for deflecting heated air into the heating compartment. The airdeflector is movable between a lowered operative position and a raisedposition. In its lowered position, the air deflector extends down overonly an upper portion of the open front of the heating compartment.

In another embodiment, this invention is directed to an oven for heatingfood, comprising a housing having a left side, a right side, a top, abottom, a back, and a front. The housing defines an oven cavitycomprising at least one heating compartment for heating food placed inthe compartment. The heating compartment has a left side wall, a rightside wall, a back wall, a top wall, a bottom wall, and an open front,without a door, in open communication with a surrounding environmentoutside the oven. Gas flow openings are provided in the left and rightside walls. The oven includes a blower for blowing gas through the gasflow openings into the heating compartment, and a heater for heating gasblowing into the heating compartment through the openings. The heatingcompartment has a side-to-side width of no more than about 14 inches. Agas dead zone at the front of the heating compartment extendssubstantially an entire height of the compartment and a fullside-to-side width of the compartment and having a dimension infront-to-rear direction of at least 2 in. The gas dead zone issubstantially free of moving gas generated by the oven during operationof the oven to heat food in the heating compartment.

In yet another embodiment, this invention is directed to an oven forheating food, comprising a housing having a left side, a right side, atop, a bottom, a back, and a front. The oven includes an oven cavityinside the housing comprising at least one heating compartment forheating food placed in the compartment. The heating compartment has aleft side wall, a right side wall, a back wall, and an open front,without a door, in open communication with a surrounding environmentoutside the oven. Gas flow openings are provided in at least one of theleft and right side walls. A blower is provided for blowing gas throughsaid gas flow openings in at least one of the left and right side wallsinto the heating compartment. A heater is provided for heating gasblowing into the heating compartment through said gas flow openings inat least one of the left and right side walls. Gas flow openings areprovided in the back wall of the heating compartment. Gas blows into theheating compartment via said gas flow openings in at least one of theleft and right side walls, and gas exhausts from the heating compartmentvia said gas flow openings in the back wall of the heating compartment.

Other objects and features will be in part apparent and in part pointedout hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective of a first embodiment of an oven of thisinvention;

FIG. 2 is a front elevation of the oven;

FIG. 3 is horizontal section taken in the plane of 3-3 in FIG. 2;

FIG. 4 is a vertical section taken in the plane of 4-4 in FIG. 2;

FIG. 5 is a vertical section taken in the plane of 5-5 in FIG. 2;

FIG. 6 is a vertical section taken in the plane of 6-6 in FIG. 2;

FIG. 7 is a vertical section taken in the plane of 7-7 in FIG. 2;

FIG. 8 is an elevation of the back wall a heating compartment of theoven;

FIG. 9 is a perspective view of the oven of FIG. 1 but with top portionsof the oven removed to show details;

FIG. 10 is a top view of FIG. 9;

FIG. 11 is a perspective view showing food-holding trays positioned inthe heating compartments;

FIG. 12 is a perspective view of a side wall panel of a heatingcompartment;

FIG. 13 is a top view similar to FIG. 3; showing a dead zone of theoven;

FIG. 14 is a perspective view of a second embodiment of a side wallpanel of a heating compartment;

FIG. 15 is a front perspective of the oven;

FIG. 16 is a front elevation of the oven of FIG. 15;

FIG. 17 is a vertical sectional view taken through the oven in a planeextending in front-to-back direction showing the flow of heated airthrough a heating compartment of the oven;

FIG. 18 is a front perspective view of a second embodiment of an oven ofthis invention;

FIG. 19 is a vertical section taken in the plane of 19-19 in FIG. 18;

FIG. 19A is a perspective of one embodiment of a tray that can be usedin the oven;

FIG. 20 is a vertical section taken in the plane of 20-20 in FIG. 18;

FIG. 21 is a view similar to FIG. 18 but with top portions of the ovenremoved to show details;

FIG. 22 is a top view of FIG. 20;

FIG. 23 is an enlarged cross-sectional view of a gas flow opening in aside wall of a heating compartment;

FIG. 24 is a front perspective view of a third embodiment of an oven ofthis invention;

FIG. 25 is a vertical section taken in the plane of 25-25 in FIG. 24;and

FIG. 26 is a vertical section taken in the plane of 26-26 in FIG. 24.

Corresponding reference characters indicate corresponding partsthroughout the drawings.

DETAILED DESCRIPTION

Referring now to the drawings, and more particularly to FIGS. 1-3, anoven of this invention for heating food with heated gas (e.g., air) isdesignated in its entirety by the reference number 20. The ovencomprises a housing 22 having an outer box-like shell 24 with a leftside 26, a right side 28, a top 32, a bottom 34, a back 36, and a front38 which is partially open. The housing 24 also includes an inner shellor liner 40 spaced inward from the sides 26, 28, back 36 and top 32 ofthe outer shell 24 to form a space 42 for receiving suitable thermalinsulation (see FIG. 3). A louvered vent 43 is provided in the top 32 ofthe outer shell 24 for venting the space 42.

The housing 22 defines an oven cavity 44 comprising at least one heatingcompartment 46 inside the liner 40. In this particular embodiment, thecavity 44 comprises two side-by-side heating compartments, namely, aleft heating compartment 46 and a right heating compartment 50. Thenumber and arrangement of heating compartments can vary. By way ofexample, the compartments may be arranged in vertical columns andhorizontal rows, and the number of compartments in each column and eachrow may vary from one to two or more. The outer shell 24 and liner 40 ofthe housing 22 are constructed of suitable material, such as sheetmetal.

The left heating compartment 46 is generally rectangular and is definedby a left side wall comprising a left side wall panel 54, a right sidewall comprising a right side panel 58, a back wall comprising a backpanel 62, a top wall comprising a top panel 66, and a bottom wallcomprising a bottom wall panel 70 spaced above the bottom 34 of thehousing 24. The front of the left heating compartment 46 is open to theenvironment surrounding the oven. The left side panel 54 of the leftheating compartment 46 is spaced from the inner liner 40 to define aleft side gas plenum 72.

Similarly, the right heating compartment 50 is generally rectangular anddefined by a left side wall comprising a left side wall panel 80, aright side wall comprising a right side panel 84, a back wall comprisingback panel 88 (which may be an integral extension of the back panel 62of the left heating compartment 46), a top wall comprising a top panel92 (which may be an integral extension of the top panel 66 of the leftheating compartment 46), and a bottom wall comprising a bottom wallpanel 96 spaced above the bottom 34 of the housing 24. The front of theright heating compartment 50 is open to the environment surrounding theoven. The right side panel 84 of the right heating compartment 50 isspaced from the inner liner 40 to define a right side gas plenum 98. Theright wall 58 of the left heating compartment 46 is spaced from the leftwall 80 of the right heating compartment to define an intermediate gasplenum 102 between the two heating compartments that extends the fullheights of the heating compartments 46, 50 (see FIG. 3).

In the illustrated embodiment, the back panels 62, 88 of the two heatingcompartments 46, 50 are spaced forward of the inner liner 40 of thehousing 22 to define a back gas plenum 106. Similarly, the top panels66, 92 of the two heating compartments 46, 50 are spaced below the innerliner 40 to define a top gas plenum 110.

The various panels forming the gas plenums of the oven are of suitablematerial, such as sheet metal.

The walls of each heating compartment 46, 50 are provided with gas flowopenings 120, 124 for the circulation of hot gas into and out of thecompartment. In particular, the left and right side walls 54, 58, 80, 84of each compartment are provided with side wall openings 120, and theback wall 62, 88 of each heating compartment is provided with back wallopenings 124 (FIG. 8). As best shown in FIGS. 9 and 10, the top panels66, 92 forming the top walls of the two heating compartments 46, 50 haveside openings 130 that communicate with respective left and right gasplenums 72, 98 of the heating compartments, and intermediate openings134 that communicate with the intermediate gas plenum 102.

The back gas plenum 106 is divided by a pair of spaced verticalpartitions 140 into a left gas flow channel 142L communicating with theleft heating compartment 46 and the top gas plenum 110, and a right gasflow channel 142R, separate from the left gas flow channel 142L,communicating with the right heating compartment 50 and the top gasplenum. As illustrated best in FIGS. 4 and 6, each of these flowchannels 142L, 142R extends substantially the full height of arespective compartment 46, 50. The flow channels communicate withrespective heating compartments 46, 50 through the openings 124 in theback panels 62, 88. Essentially all gas exiting the left heatingcompartment 46 flows into the left gas flow channel 142L, andessentially all gas exiting the right heating compartment 50 flows intothe right gas flow channel 142R.

A left blower 150L is suitably positioned in the left gas flow channel142L, e.g., adjacent its upper end, for circulating gas along a gas flowpath through the left heating compartment 46. In particular, gas fromthe blower 150L enters the top plenum 110; flows via respective leftside and intermediate openings 130, 134 in the top panel 66 down intothe left and intermediate gas plenums 72, 102; flows via the gas flowopenings 120 in the left and right panels 54, 58 into the left heatingcompartment 46; and exits the compartment via the openings 124 in theback panel 62 into the left gas flow channel 142L for flow back to theblower 150L.

Similarly, a right blower 150R is suitably positioned in the right gasflow channel 142R, e.g., adjacent its upper end, for circulating gasalong a gas flow path through the right heating compartment 50. Inparticular, gas from the right blower 150R enters the top plenum 110;flows via respective right side and intermediate openings 130, 134 inthe top panel 92 down into the right and intermediate plenums 98, 102;flows via the gas flow openings 120 in the left and right panels 80, 84into the right heating compartment 50; and exits the compartment via theopenings 124 in the back panel 88 into the right gas flow channel 142Rfor flow back to the right blower 150R.

Referring to FIGS. 9 and 10, a left heater 160L is provided in the topplenum 110 generally at a location over the left heating compartment 46for heating gas from the discharge of the left blower 150L. Similarly, aright heater 160R is provided in the top plenum 110 generally at alocation over the right heating compartment 50 for heating gas from thedischarge of the right blower 150R. Alternatively, the heaters 160L,160R can be placed immediately upstream from the blower inlets. By wayof example but not limitation, each heater can comprise one or moreelectric resistance heating elements.

Referring to FIG. 11, a suitable support system 170 is provided forsupporting food in each compartment at adjustable or non-adjustablelevels within the compartment. In the illustrated embodiment, thesupport system 170 includes one or more supports 174, each of whichcomprises horizontal rods 176 having ends sized for reception in theopenings 120 in the side walls panels of the heating compartment, andone or more food holders 180 (e.g., trays or racks) supported by therods. The rods 176 are removable so that each holder 180 is adjustableup and down in the heating compartment, as needed or desired, simply byinserting the rods in a different set of side wall openings 120.

Desirably, each heating compartment 46, 50 has a side-to-side width ofno more than about 14 inches, exemplary dimensions being anywhere in therange of 4-14 inches (e.g., 4, 6, 8, 10, 12, or 14 inches). Therelatively narrow width of each compartment 46, 50 insures that hot gasentering the heating compartment via the left and right side openings120 contacts the entire surface of each food product in the compartment,even the portions toward the middle of the compartment. The shorterdistances required for gas flow results in good thermal heat transfer tothe food and reduced temperature differential across the food (i.e.,more uniform heating of the food).

Desirably, the openings 120 in the left and right side walls 54, 58, 80,84 of each heating compartment 46, 50 are spaced a substantial distancerearward from the open front of the compartment to create a gas deadzone 200 at the front of each heating compartment extendingsubstantially an entire height of the compartment and a fullside-to-side width of the compartment. The zone 200 has a dimension infront-to-rear direction of at least 2 in., e.g., 2, 3, 4, 5, or 6 in. ormore. The gas dead zone 200 is illustrated in FIG. 3. The gas dead zone200 is also illustrated in FIG. 13 in the heating compartment 50. Thegas dead zone 200 of this embodiment has a generally rectangularhorizontal cross-section. In other words, a depth 200D of the gas deadzone 200 is substantially constant across the full side-to-side width ofthe compartment 50. The gas dead zone 200 may have different shapes, asdiscussed in more detail below. During operation of the oven 20, thiszone 200 is substantially free of moving gas generated by the oven. Thezone 200 acts as a thermal barrier for preventing substantial loss ofheat from the heating compartment 46, 50. As a result, there is no needfor a door at the front of the compartment, making access to thecompartment more convenient for loading and unloading of food.

The gas flow into and out of each heating compartment 46, 50 is closelycontrolled by the pattern and size of gas openings 120, 124 in the wallsof the compartment. A representative arrangement of openings 120, 124 isdescribed below for an oven in which each of the left and right heatingcompartments has a height of about 15.0 in., a width of about 8.0 in.,and a depth of about 19.0 in.

FIG. 4 illustrates the left panel 54 defining the left side wall of theleft heating compartment 46. The gas flow openings 120 in the panel 54are arranged in four vertical arrays A1-A4 spaced at different distancesD1-D4 from the front of the heating compartment 46, e.g., 3.5 in., 8.0in., 13.5 in., and 15.5 in., respectively. (D1 corresponds to the depthof the aforementioned gas dead zone 200.) Each array A1-A4 of openingscomprises a matrix of columns and rows extending from adjacent the topof the panel 54 to adjacent the bottom of the panel. The width of thearray A1 (i.e., the number of columns in the matrix) varies in thevertical direction to form a series of relatively wide vertically-spacedclusters C1-C3 of openings. The widths of the second, third, and fourtharrays A2-A4 are identical (two columns per array). The openings have adiameter of about 0.290 in., a vertical center-to-center spacing ofabout 0.50 in., and a horizontal center-to-center spacing of about 0.50in. Other dimensions are possible. Further, while the openings shown inthe drawings are of the same size, they may differ in size.

FIG. 5 illustrates the right panel 58 defining the right side wall ofthe left heating compartment 46. The gas flow openings 120 in the panel58 are arranged in four vertical arrays A5-A8 spaced at differentdistances D5-D8 from the front of the heating compartment 46, e.g., 3.5in., 8.0 in., 13.5 in., and 15.5 in., respectively. (D5 corresponds tothe depth J of the aforementioned gas dead zone 200.) Each array A5-A8of openings comprising a matrix of columns and rows extending fromadjacent the top of the panel 58 to adjacent the bottom of the panel.The width of the array A5 (i.e., the number of columns in the matrix)varies in the vertical direction to form a series of relatively widevertically-spaced clusters C4-C6 of openings. The clusters C4-C6 arestaggered vertically with respect to the clusters C1-C3 of the leftpanel 54 to provide more uniform gas flow into the heating compartment46. The widths of the arrays A6-A8 are identical (two columns perarray). The openings have a diameter of about 0.290 in., a verticalcenter-to-center spacing of about 0.50 in., and a horizontalcenter-to-center spacing of about 0.50 in. Other dimensions arepossible. Further, while the openings shown in the drawings are of thesame size, they may differ in size.

FIG. 6 illustrates the left panel 80 of the right heating compartment50. The gas flow openings 120 in the panel 80 are arranged in fourvertical arrays A9-A12 spaced at different distances D9-D12 from thefront of the heating compartment 50, e.g., 3.5 in., 8.0 in., 13.5 in.,and 15.5 in., respectively. (D9 corresponds to the depth of theaforementioned gas dead zone 200.) Each array A9-Al2 of openingscomprises a matrix of columns and rows extending from adjacent the topof the panel 80 to adjacent the bottom of the panel. The width of thearray A9 (i.e., the number of columns in the matrix) varies in thevertical direction to form a series of relatively wide vertically-spacedclusters C7-C9 of openings. The widths of the arrays A6-A8 are identical(two columns per array). The openings 120 have a diameter of about 0.290in., a vertical center-to-center spacing of about 0.50 in., and ahorizontal center-to-center spacing of about 0.50 in. Other dimensionsare possible. Further, while the openings shown in the drawings are ofthe same size, they may differ in size. In the illustrated embodiment,the openings 120 in the panel 80 have the same pattern and size as theopenings 120 in the right panel 58 of the left heating compartment 46.

FIG. 7 illustrates the right panel 84 of the right heating compartment50. The gas flow openings 120 in the panel 84 are arranged in fourvertical arrays A13-A16 spaced at different distances D13-D16 from thefront of the heating compartment 50, e.g., 3.5 in., 8.0 in., 13.5 in.,and 15.5 in., respectively. (D13 corresponds to the depth of theaforementioned gas dead zone 200.) Each array A13-A16 of openingscomprises a matrix of columns and rows extending from adjacent the topof the panel 84 to adjacent the bottom of the panel. The width of thearray A13 (i.e., the number of columns in the matrix) varies in thevertical direction to form a series of relatively wide vertically-spacedclusters C10-C12 of openings. The clusters C10-C12 are staggeredvertically with respect to the clusters C7-C9 of the left panel 80 ofthe right heating compartment 50 to provide more uniform gas flow intothe heating compartment. The widths of the arrays A14-A16 are identical(two columns per array). The openings 120 have a diameter of about 0.290in., a vertical center-to-center spacing of about 0.50 in., and ahorizontal center-to-center spacing of about 0.50 in. Other dimensionsare possible. Further, while the openings shown in the drawings are ofthe same size, they may differ in size. In the illustrated embodiment,the openings 120 in the panel 84 have the same pattern and size as theopenings 120 in the left panel 54 of the left heating compartment 46.

In general, the gas flow openings 120 in the left and right panels 54,58, 80, 84 of each heating compartment 46, 50 are arranged and sizedsuch that gas is delivered substantially uniformly into the heatingcompartment in a vertical direction from adjacent the top wall 66, 92 ofthe heating compartment to adjacent the bottom wall 70, 96 of theheating compartment, and such that gas is delivered substantiallyuniformly into the heating compartment from a location generallyimmediately rearward from the gas dead zone 200 to the back wall 62, 88of the heating compartment. The pattern and size of the openings 120will vary according to such factors as the height, width, and depthdimensions of the heating compartment 46, 50, the number and verticalspacing of the food supports 174 in the compartment, and the velocityand volume of the gas flowing through the compartment.

FIG. 8 illustrates the back panels 62, 88 defining the back walls of theleft and right heating compartments 46, 50, respectively. In theillustrated embodiment, the back panels 62, 88 are integrally formed asone piece of sheet metal. In other embodiments, they may be formed asseparate panels. The openings 124 in the left panel 62 are arranged in afirst array A17 providing communication between the left heatingcompartment 46 and the left gas flow channel 142L of the back plenum106, and the openings 124 in the right panel 88 are arranged in a secondarray A18 (identical to the first array A17 in this embodiment)providing communication between the right heating compartment 50 and theright gas flow channel 142R of the back plenum 106. Each of the arraysA17, A18 comprises five vertically-spaced groups of openings, and eachgroup comprises a matrix of columns and rows covering a major portion ofthe back wall of a respective compartment. The openings have a diameterof about 0.290 in., a vertical center-to-center spacing of about 0.50in., and a horizontal center-to-center spacing of about 0.50 in. Otherdimensions are possible.

FIG. 10 illustrates the top panels 66, 92 defining the top walls of theleft and right compartments 46, 50, respectively. Each group of sideopenings 130 includes a plurality of rectangular openings (three suchopenings being shown) for flow of gas from the top gas plenum 110 torespective side gas plenums 72, 98. The rear and center openings 130closest the blowers 150L, 150R are smaller than the forward opening 130farthest from the blowers to provide for a more uniform distribution ofgas from the top plenum 110 to respective side plenums 72, 98. The groupof intermediate openings 134 includes a plurality of rectangularopenings (four such openings being shown) for flow of gas from the topgas plenum 110 to the intermediate gas plenum 102. The side andintermediate openings 130, 134 may vary in number and shape.

In the illustrated embodiment, the left and right heating compartments46, 50 are of the same size. However, it will be understood that heatingcompartments may vary in size with respect to one another. Regardless ofsize, however, the arrangement of the gas flow openings 120, 124 shouldbe such that the gas moving through the compartment has good heattransfer contact with the food substantially uniformly over the entiresurface of the food in the compartment.

The left and right blowers 150L, 150R used in the two-compartment ovendescribed above, may be tangential blowers, mounted side-by-side in adouble housing such that the gas is discharged from the blowers throughopenings in a vertical flange 210 projecting up from the top panels 66,92 (FIG. 9). By way of example but not limitation, each blower may havean impeller diameter of 65 mm, a static pressure in its discharge plenumof about 0.036 IWC, and generate a gas flow rate of 165 cubic feet perminute.

Also, by way of example, each of the left and right heaters 160L, 160Rmay include a first relatively longer finned electric heating element214 extending widthwise of the oven and a second relatively shorterelectric heating element 216 spaced rearward from and generally parallelto the first element. The elements 214, 216 of each heater 160L, 160Rare secured to a respective top panel 66, 92 and extend between the sideand intermediate openings 130, 134 of the panel above a respectiveheating compartment 46, 50. Other locations are possible. In oneexample, each heating element 214, 216 has a power output of 500 watts,for a total output of 1000 watts per heater 160L, 160R, but this poweroutput will vary according to the heating requirements of the oven.

Desirably, the oven has a suitable control system 230 for operating theoven. The system is housed in a control housing 234 secured to the front38 of the oven housing 22. The control system 230 includes an on/offpower switch 238 and an operator input 240 for inputting desiredoperational information such as compartment temperature, heating time,and specific programs for heating (e.g., rethermalizing) and/or holdingfood in the oven. The control system 230 also includes a processor (notshown) for processing such information and controlling the blowers 250L,250R and heaters 260L, 260R accordingly. It is preferable (although notessential) to configure the system such that the operation of theblowers 150L, 150R may be controlled independent of one another, andsuch that the operation of the heaters 160L, 160R may be controlledindependent of one another. This allows each heating compartment 46, 50to be operated in a “modular” fashion independent of one another forgreater flexibility in the use of the oven. By way of example, differentfoods may be heated in different heating compartments. Further, thenumber of compartments used at any given time may be tailored to meetthe demand.

A fan 250 is provided for circulating air through the control systemhousing 234 to cool the various electronic components of the controlsystem.

In a second embodiment (not shown), the oven 20 has a configurationsimilar to the first embodiment (FIGS. 1-11) but is altered to have amodified circulation of gas into and out of the compartments 46, 50. Inparticular, gas flows into the compartments 46, 50 through the openings120 in respective side walls 54 and 84, and gas flows out of thecompartments through the openings 120 in respective side walls 58 and 80as well as through the openings 124 in the back panels 62, 88. Thus, gasflows into each compartment 46, 50 through one wall 54, 84, and flowsout of each compartment through two walls 58, 80, 62, 88.

The structure of the second embodiment is different from the embodimentdescribed above in that the second embodiment lacks the intermediateopenings 134 that enable communication between the top gas plenum 110and the intermediate gas plenum 102. The second embodiment hasadditional openings 124 in the back panels 62, 88 that are disposedinboard of the side walls 58 and 80 to enable communication between theintermediate gas plenum 102 and the space between the verticalpartitions 140 in the back gas plenum 106. In addition, openings areprovided in the vertical partitions 140 to enable communication amongthe space between the partitions and the left and right flow channels142L, 142R.

Referring to the left heating compartment 46, gas flow generated by theblowers 150L, 150R enters the top gas plenum 110; flows via the leftside openings 130 in the top panel 66 down into the left gas plenum 72;flows via the gas flow openings 120 in the left panel 54 into thecompartment 46; and exits the compartment via the openings 120 in theright panel 58 and the openings 124 in the back panel 62. Gas flow isreturned to the blower 150L via the left gas flow channel 142L, whichcollects gas flow directly from the openings 124 in the back panel 62and from the openings 120 in the side wall 58 through the intermediategas plenum 102 and the space between the vertical partitions 140.

Referring to the right heating compartment 50, gas flow generated by theblowers 150L, 150R enters the top gas plenum 110, flows via the rightside openings 130 in the top panel 92 down into the right gas plenum 98;flows via the gas flow openings 120 in the right panel 84 into thecompartment 50; and exits the compartment via the openings 120 in theleft panel 80 and the openings 124 in the back panel 88. Gas flow isreturned to the blower 150R via the right gas flow channel 142R, whichcollects gas flow directly from the openings 124 in the back panel 88and from the openings 120 in the side wall 80 through the intermediategas plenum 102 and the space between the vertical partitions 140.

In the second embodiment, the arrangement of the gas flow openings 120,124 may vary to accomplish a desired gas movement through thecompartments 46, 50 to impart good heat transfer contact with the foodsubstantially uniformly over the entire surface of the food in thecompartments. For example, in one test, 75% of the openings in the rearpanels 62 and 88 shown in FIG. 8 were absent or blocked. Otherarrangements of the gas flow openings 120, 124 may be used to impartdesired gas movement through the compartments 46, 50 to impart good heattransfer contact with the food substantially uniformly over the entiresurface of the food.

In a third embodiment, the oven 20 has a configuration similar to thefirst embodiment but has modified side wall panels. A representativemodified side wall panel 54′, 80′ is illustrated in FIG. 12. In general,the third embodiment is different from the first embodiment in that theside wall panels of the third embodiment have at least some louvered gasflow openings 120L that direct gas exiting the left, right, andintermediate gas plenums 72, 98, and 102 through the louvered openingstoward the rear of the heating compartments 46, 50. The louveredopenings 120L assist in preventing substantial loss of heat from theheating compartments 46, 50 to ambient through the open fronts of thecompartments. As a result, there is no need for a door at the front ofeach compartment.

The side wall panel illustrated in FIG. 12 is configured for use as theleft side panel 54′ of the left side heating compartment 46 and/or theleft side panel 80′ of the right side heating compartment 50. Thecorresponding right side panels 58′, 84′ (not shown) are generally amirror image of the illustrated panel 54′, 58′, but may be different.

The gas flow openings 120, 120L of the panel 54′, 80′ are arranged inthree vertical arrays A19-A21 spaced at different distances D17-D19 fromthe front of the heating compartment 46, e.g., 1.0 in., 5.0 in., and14.5 in., respectively. Each array A19-A21 of openings comprises amatrix of columns and rows extending from adjacent the top of the panel54′ to adjacent the bottom of the panel.

The first array A19 comprises the louvered gas flow openings 120L. Inthe illustrated embodiment, the array comprises six columns and threerows of louvered openings 120L. Louvers 120L′ direct gas entering thecompartment through the openings in a direction generally toward therear of the compartment 46 and toward a centerline 250 (FIG. 13)extending from the front to the rear of the compartment. The louvers120L′ direct gas flow at an angle 275′ (FIG. 13) less than or equal toseventy-five degrees with respect to the side wall panel 54′. In theillustrated embodiment, the angle 275′ is approximately forty-fivedegrees. Accordingly, the louvered openings 120L assist in preventingsubstantial loss of heat from the heating compartment 46. In addition,the louvered openings 120L assist in directing heated gas toward theopenings in the back wall panel 62 for return to the left gas flowchannel 142L. Other types, configurations, and arrangements of louveredor baffled openings 120L may be used to accomplish desired gas flow.

The third embodiment has a gas dead zone 200′ at the front of thecompartment similar to the first embodiment, but the gas dead zone 200′in the third embodiment has a different shape than in the firstembodiment. FIG. 13 illustrates the gas dead zone 200 of the firstembodiment in the right compartment 50 (i.e., the compartment 50 hasleft and right side wall panels 80, 84 as described with respect to thefirst embodiment), and illustrates the gas dead zone 200′ of the thirdembodiment in the left compartment 46 (i.e., the compartment 46 has leftand right side wall panels 54′, 58′ as described with respect to thethird embodiment). As discussed above, the gas dead zone 200 of thefirst embodiment has a generally rectangular horizontal cross-section.The depth 200D of the gas dead zone 200 is substantially constant acrossthe full side-to side width of the compartment 50.

In the third embodiment, the gas dead zone 200′ has a generallytrapezoidal horizontal cross-section. This trapezoidal shape resultsfrom gas flowing from the louvered openings 120L into the compartment.As in the first embodiment, the gas dead zone 200′ extends substantiallythe entire height of the compartment 46 and the full side-to-side widthof the compartment at the open front of the compartment. In addition,the gas dead zone 200′ has a dimension (e.g., dimension 200D′ shown inFIGS. 12 and 13) in the front-to-rear direction of at least at least 2in., e.g., 2, 3, 4, 5, or 6 in. or more. However, the depth 200D′ of thegas dead zone 200′ (i.e., the front to rear dimension of the gas deadzone) varies across the side-to-side width of the compartment 46. Inparticular, the depth 200D′ tapers proximate the side wall panels 54′,58′ from the open front toward the rear of the compartment 46 because ofgas flow entering the compartment through the louvered openings 120L.The gas dead zone 200′ tapers at generally the same angle 275′ at whichgas flows from the louvered openings 120L. Other embodiments may havegas dead zones of different or varying shapes.

As in the gas dead zone 200 of the first embodiment, the gas dead zone200′ is substantially free of moving gas generated by the oven duringoperation of the oven 20. The gas dead zone 200′ acts as a thermalbarrier for preventing substantial loss of heat from the heatingcompartment 46. As a result, there is no need for a door at the front ofthe compartment, making access to the compartment more convenient forloading and unloading of food.

Referring again to FIG. 12, the second and third arrays A20 and A21comprise openings 120 of similar size and shape as the openings 120 ofthe first embodiment. For example, the openings 120 have a diameter ofabout 0.290 in., a vertical center-to-center spacing of about 0.50 in.,and a horizontal center-to-center spacing of about 0.50 in. Varyingnumbers of arrays may be used, and arrays having different numbers ortypes of openings and different widths (i.e., different numbers ofcolumns) may be used.

In a fourth embodiment, the oven 20 has a configuration similar to thethird embodiment but has different side wall panels. A representativemodified side wall panel 54″, 58″ of the fourth embodiment isillustrated in FIG. 14. Instead of having louvered openings, themodified side wall panel 54″, 58″ of the fourth embodiment has openings120C in at least one surface 300 of the side wall panel that is orientedtoward the rear of the heating compartment 46. In other words, theopenings 120C are provided in one or more surfaces 300 of the side wallpanel 54″, 58″ that face or are angled toward the rear of the heatingcompartment 46.

The gas flow openings 120, 120C of the panel 54″, 58″ are arranged inseven vertical arrays A22-A28 spaced at different distances D20-D26 fromthe front of the heating compartment 46, e.g., 1.5 in., 3.5 in., 5.5in., 6 in., 8 in., 12 in., and 14 in., respectively. Each array A22-A28of openings comprises a matrix of columns and rows extending fromadjacent the top of the panel 54″ to adjacent the bottom of the panel.

In the representative side panel 54″, 58″ illustrated in FIG. 14, thepanel has a corrugated section 350 proximate the open front of the oven20. The corrugated section 350 comprises ridges 351 extending verticallyalong the side wall panel 54″, 58″. Each ridge 351 comprises a surface300 oriented generally toward the rear of the heating compartment and asurface 301 oriented generally toward the open front of the oven 20. Theopenings 120C of the first, second, and third arrays A22-A24 areprovided on the surfaces 300 oriented toward the rear of the heatingcompartment 46. The surfaces 300 are oriented so that gas flowing fromthe openings 120C is directed generally toward the rear of thecompartment 46 and toward the centerline 250 extending from the front tothe rear of the compartment. Gas flows from the openings 120C at anangle 275″ (FIG. 13) less than or equal to seventy-five degrees, morepreferably sixty degrees, and more preferably forty-five degrees, withrespect to the side wall panels 54″, 58″. In the illustrated embodiment,the angle 275″ is approximately forty-five degrees. Other angles may beused. In addition, the surfaces 300 may be oriented differently so thatopenings 120C in different ones of the surfaces direct gas flow towardthe rear of the compartment 46 at different angles with respect to theside wall panel.

The gas dead zone 200″ of this embodiment is similar to the gas deadzone 200′ of the third embodiment (i.e., the side wall panels 54″, 58″of the fourth embodiment installed in the compartment 46 would produceapproximately the same gas dead zone 200′ as in the third embodiment).The gas dead zone 200″ has a depth 200D″ that varies along theside-to-side width of the compartment 46. More specifically, the depth200D″ tapers proximate the side wall panels 54″, 58″ from the open fronttoward the rear of the compartment 46 because of gas flow entering thecompartment through the openings 120C. The gas dead zone 200″ tapers atgenerally the same angle 275″ at which gas flows from the openings 120C.Other embodiments may have gas dead zones of different or varyingshapes. As in previous embodiments, the gas dead zone 200″ acts as athermal barrier for preventing substantial loss of heat from the heatingcompartment 46.

Referring again to FIG. 14, the fourth to seventh arrays A25-A28 maycomprise openings 120 of similar size and shape as the openings 120 ofthe embodiments described above. Varying numbers of arrays may be used,and arrays having different numbers or types of openings and differentwidths (i.e., different numbers of columns) may be used.

In a fifth embodiment, illustrated in FIGS. 15 and 16, the oven 20 has aconfiguration similar to the first embodiment but includes baffles 400within the heating compartments 46, 50 on the side wall panels 54, 58,80, 84 for deflecting gas exiting the holes 120 downward into an opentop 180′ of a food holder 180 (e.g., tray). The openings 120 in the sidewall panels 54, 58, 80, 84 may have various arrangements. In theillustrated arrangement, clusters C13 and C14 of openings 120 on eachside wall panel 54, 58, 80, 84 extend along substantially the entiredepth of the heating compartments 46, 50. The baffles 400 overhang atleast some of the openings 120 to direct gas flowing from those openingsinto the heating compartment 46 generally downward to contact foodwithin the holder 180. The baffles 400 are desirably positionedvertically within the heating compartments 46, 50 with respect to thesupport system 170 in contemplation of characteristics (e.g., height,width) of the desired food holders 180 to be used so that gas deflecteddownward by the baffles 300 is directed from a suitable height and at asuitable angle 450 (FIG. 16) so that the gas flows through the open topof the holder and contacts the food in the holder when the holder ispositioned on the support system 170. The angle 450 may be generallybetween five and seventy-five degrees with respect to the side wallpanel. The angle is more desirably between twenty and sixty degrees, andmore desirably between forty and fifty degrees. In the illustratedembodiment, the angle 450 is approximately forty-five degrees.

The illustrated baffles 400 extend approximately the entirefront-to-rear depth of the heating compartments 46, 50, but baffles ofother lengths may be used. In addition other types of baffles may beused. For example, louvered openings may be used to direct flow of gasas desired.

In a sixth embodiment, illustrated in FIG. 17, the oven 20 again has aconfiguration similar to the first embodiment but is different in thatthe oven includes vanes 500 positioned and supported within the left,right, and/or intermediate gas plenums 72, 98, 102 to counteract forwardvelocity of gas flowing within the plenums to prevent the gas frombreaching the gas dead zone 200 in the front of the compartments 46, 50after the gas flows into the compartments through the openings 120 inthe side wall panels 54, 58, 80, 84. FIG. 17 illustrates representativevanes 500 positioned and supported in the intermediate plenum 102.

As explained above with respect to the first embodiment, gas from theleft blower 150L travels along the top gas plenum 110, flows into theintermediate gas plenum 102, and then flows into the heating compartment46 via the openings 120 in the right side wall panel 58. Some gasentering the heating compartment 46 may tend to flow toward the openfront of the oven 20 as a result of the gas molecules having residualvelocity in that direction from the blower 150L. The vanes 500 desirablysubstantially counteract residual forward velocity to prevent gasmolecules entering the heating compartment 46 from breaching the gasdead zone 200 in the front of the compartment to prevent substantialloss of heat from the heating compartment. Moreover, the vanes 500 maybe configured to turn the flow of gas toward the rear of the compartment46 so that the gas molecules tend to flow toward the rear of thecompartment upon entry into the compartment through the openings 120 inthe right side wall panel 58.

Gas dead zones as described herein may have different shapes indifferent embodiments. Although the gas dead zone 200 and the gas deadzones 200′ and 200″ have generally rectangular and generally trapezoidalhorizontal cross-sections, respectively, other gas dead zones may havedifferent horizontal cross-sections. For example, a gas dead zone mayhave a generally triangular horizontal cross section. In someembodiments, the gas dead zone has the same horizontal cross-section(e.g., rectangular or trapezoidal) over substantially the entire heightof the heating compartment 46, 50. However, in other embodiments, thedimensions of the gas dead zone may vary over the height, across thewidth, and along the depth of the heating compartment 46, 50.

FIGS. 18-23 show another embodiment of an air handling unit or oven ofthis invention, generally designated 500. The oven 500 is similar inconstruction to the oven 20 of the first embodiment. The oven 500comprises a housing 504 defining an oven cavity comprising a pluralityof side-by-side heating compartments 508. (Five such compartments 508are shown but this number can vary.) Desirably, each heating compartmenthas a side-to-side width of no more than about 14 inches. Heated air iscirculated through the compartments 508 in much the same manner as inthe oven 20 of the first embodiment. As shown in FIGS. 19, 21, and 22,blowers 512 positioned at the upper end of a rear plenum 516 in the ovenblow air over electric resistance heaters 520 positioned in an upperplenum 524 of the oven (see FIG. 19). The heated air flows down throughopenings 528 into plenums 534 at opposite sides of the heatingcompartments 508 and then into the compartments 508 through gas flowopenings 540 in the left and right side walls 544, 548 of thecompartments (FIGS. 20-22). Air from the heating compartments 508 isexhausted into the rear plenum 516 through openings 550 in the backwalls 556 of the compartments (see FIG. 20).

However, the oven 500 differs from the previous embodiments in that ithas no dead zone at the open front 560 of each compartment 508. Further,unlike prior art ovens, there is no air curtain at the open front 560 ofeach compartment. The gas flow openings 540 in the side walls 544, 548of the compartments are configured such that substantially all of thegas blowing into the heating compartment 508 is directed generally awayfrom the open front 560 of the compartment. FIG. 23 illustrates one suchgas flow opening 540 in a respective side wall 544, 548. The opening 540is generally oval in shape, having a longitudinal axis 564, andcomprises an angled nozzle 570 that directs air flowing through theopening at an acute angle 574 in the range of 10-45 degrees (e.g., about15 degrees) relative to the side wall. Other gas flow openingconfigurations are possible.

Referring to FIGS. 19 and 19A, supports 580 are provided on the sidewalls 544, 548 of the heating compartments 508 for supporting trays 582at vertically spaced elevations in the heating compartment. The trayshave outwardly projecting peripheral flanges 584 around their open tops.The flanges 584 are dimensioned to rest on the supports 580 such thattrays hang down from the supports. Other supporting arrangements arepossible. Further, the supports 580 are configured for supporting thetrays at an upward inclination toward the back wall 556 of the heatingcompartment 508. The angle of inclination 586 (e.g., 10-20 degrees)allows a user of the oven to readily observe the contents of the trays.

The gas flow openings 540 are grouped in a plurality of arrays 590comprising vertical columns of openings and rows of openings 540extending generally in front-to-back direction with respect to theheating compartment. The arrays 590 are spaced at vertical intervals atlocations corresponding to the areas above the supports 580 and the opentops of the trays 582. Further, the arrays 590 are configured to extendgenerally at the same angle of inclination 586 as the supports 580 andtrays 582 (e.g., 10-20 degrees). Although each array 590 as a whole isupwardly inclined toward the back wall 556 of the compartment 508, thelongitudinal axis 564 of each individual opening 540 extends generallyhorizontally. The arrangement is such that heated air discharged throughthe gas flow openings 540 of each array 590 passes over the top of anytray supported immediately below the array and under the bottom of anytray supported immediately above the array. As a result, food in eachtray is uniformly heated from above and below.

Generally horizontal arrays 596 of gas flow openings 540 are providedadjacent the lower ends of the side walls 544, 548 of each heatingcompartment 508. During operation of the oven 500, heated air flowingthrough these arrays 596 of openings functions to warm cooler make-upair flowing into the heating compartments 508 via the open fronts 560 ofthe compartments.

Referring to FIGS. 18 and 19, an air deflector 600 is mounted adjacentthe upper end of each heating compartment 508 for deflecting heated airinto the heating compartment. In the illustrated embodiment, the airdeflector 600 comprises a single rectangular transparent panel (alsodesignated 600) extending across the open fronts 560 of all five heatingcompartments 508. Alternatively, a separate air deflector can beprovided for each compartment. The deflector 600 is pivoted on brackets606 at the front of the oven housing 504 for movement between a raisedposition (shown in phantom lines in FIG. 19) to enable removal of one ormore trays 582 from a heating compartment or compartments 508 and alowered operative position (shown in solid lines in FIG. 19) in whichheated air rising in the heating compartments is deflected back into thecompartments. This deflection reduces the escape of heated air from theoven, thus increasing efficiency and decreasing any negative impactescaping air might have on the surrounding environment. A holder 610 isprovided on the deflector for holding a menu, instructions, or othermaterial to be observed by a user of the oven.

Referring to FIG. 19, the open front of each compartment has an overallvertical height represented by the dimension 602. The air deflector 600is dimensioned such that, when in its lowered position, it has avertical height represented by the dimension 604. Desirably, the ratioof dimension 604 to 602 is less than one-half, and even more desirablyno more than about one-third. As a result, when the deflector 600 is inits lowered position, it extends down over only the upper portion of theopen front 560 of each heating compartment 508.

In its lowered position, the air deflector panel 600 desirably rests onsupport members 614 adjacent opposite sides of the oven housing 504(FIGS. 18 and 19). These support members 614 support the panel at anacute angle 620 (e.g., 15 degrees) sloping in a forward direction downand away from the open front 560 of each compartment 508. This slopeincreases the volume of heated gas deflected by the panel back into theheated compartments. In other embodiments, the air deflector 600 mayassume a substantially vertical orientation when in its loweredposition.

FIGS. 24-26 show another embodiment of an oven of this invention,generally designated 700. The oven 700 is similar to the oven 20 of thefirst embodiment. Supports 704 are provided for supporting trays 708 ina generally horizontal orientation (with no substantial upward tilt).Gas flow openings 710 in the side walls of each heating compartment areconfigured in generally horizontal arrays at locations generallycorresponding to the areas above the open tops of the trays 708. Heatedgas discharged through the openings 710 of each array 714 flows acrossthe top of any tray 708 immediately below the array and flows across thebottom of any tray immediately above the array. Heated gas exits eachheating chamber 720 through openings (not shown) in the back wall 724,as described in previous embodiments.

When introducing elements of the present invention or the preferredembodiments(s) thereof, the articles “a”, “an”, “the” and “said” areintended to mean that there are one or more of the elements. The terms“comprising”, “including” and “having” are intended to be inclusive andmean that there may be additional elements other than the listedelements.

In view of the above, it will be seen that the several objects of theinvention are achieved and other advantageous results attained.

As various changes could be made in the above constructions and methodswithout departing from the scope of the invention, it is intended thatall matter contained in the above description and shown in theaccompanying drawings shall be interpreted as illustrative and not in alimiting sense.

What is claimed is:
 1. An oven for heating food, comprising a housinghaving a left side, a right side, a top, a bottom, a back, and a front,an oven cavity inside the housing comprising at least one heatingcompartment for heating food placed in the compartment, the heatingcompartment having a left side wall, a right side wall, a back wall, atop wall, a bottom wall, and an open front, without a door, in opencommunication with a surrounding environment outside the oven, gas flowopenings in at least one of the left and right side walls, a blower forblowing gas through the gas flow openings in at least one of the leftand right side walls into the heating compartment, a heater for heatinggas blowing into the heating compartment through the gas flow openings,and wherein the gas flow openings are configured such that substantiallyall of the gas blowing into the heating compartment is directedgenerally away from the open front of the compartment.
 2. The oven setforth in claim 1, wherein said back wall has gas flow openings for exitof gas from the at least one heating compartment.
 3. The oven set forthin claim 2, wherein the heating compartment is a left heatingcompartment, and wherein the oven further comprises a right heatingcompartment, the right heating compartment having a left side wall, aright side wall, a back wall, a top wall, a bottom wall, and an openfront, without a door, in open communication with a surroundingenvironment outside the oven, the oven further comprising anintermediate gas plenum between the left and right heating compartments,said intermediate gas plenum having a left wall defined by the rightside wall of the left heating compartment and a right side wall definedby the left side wall of the right heating compartment.
 4. The oven setforth in claim 3, further comprising a left gas plenum adjacent the leftside wall of the left heating compartment, a right gas plenum adjacentthe right side wall of the right heating compartment, a back gas plenumadjacent the back walls of the left and right heating compartments, anda top gas plenum adjacent the top walls of the left and right heatingcompartments, said left and right gas plenums, back gas plenum, top gasplenum, and intermediate gas plenum communicating with one another todefine flow paths for circulating gas through said left and rightheating compartments.
 5. The oven set forth in claim 4, wherein saidback gas plenum comprises a left gas flow channel communicating with theleft heating compartment and top gas plenum, and a right gas flowchannel, separate from the left gas plenum channel, communicating withthe right heating compartment and the top gas plenum.
 6. The oven setforth in claim 5, wherein said left and right gas flow channels includerespective upper and lower ends, and wherein said blower is a leftblower located adjacent the upper end of the left gas flow channel, andwherein said oven further comprises a right blower located adjacent theupper end of the right gas flow channel.
 7. The oven set forth in claim6, wherein said heater is a left heater located in the top gas plenumgenerally above the left heating compartment for heating gas dischargedfrom the left blower, and wherein said oven further comprises a rightheater located in the top gas plenum generally above the right heatingcompartment for heating gas discharged from the right blower.
 8. Theoven set forth in claim 1, wherein said gas flow openings are located inthe left and right side walls of the heating compartment and arrangedbetween the top and bottom walls of the heating compartment such thatgas is delivered substantially uniformly into the heating compartmentfrom adjacent the top wall of the heating compartment to adjacent thebottom wall of the heating compartment.
 9. The oven set forth in claim1, wherein said blower operates to deliver heated gas into the heatingcompartment via said gas flow openings at a velocity sufficient for themoving gas to contact food located midway between the left and rightside walls of the compartment.
 10. The oven set forth in claim 1,wherein the blower blows gas through the gas flow openings in one of theleft and right side walls into the heating compartment, and the gas flowopenings in the other of the left and right side walls is for exit ofgas from the at least one heating compartment.
 11. The oven set forth inclaim 1, wherein the heating compartment has a side-to-side width of nomore than about 14 inches.
 12. The oven set forth in claim 1, furthercomprising supports in the oven for supporting trays at verticallyspaced elevations in the heating compartment, and wherein the gas flowopenings are grouped in a plurality of arrays extending generally infront-to-back direction with respect to the heating compartment, saidarrays being spaced at vertical intervals corresponding to saidelevations at which the trays are supported such that heated gasdischarged through the gas flow openings of an array flows across thetop of any tray immediately below the array and flows across the bottomof any tray immediately above the array.
 13. The oven set forth in claim12, wherein said supports are configured for supporting the trays at anangle of inclination that extends upward and rearward in the heatingcompartment, and wherein the gas flow openings of the arrays arearranged with respect to one another to provide each array with a shapeextending generally at said angle of inclination upward and rearward inthe heating compartment.
 14. The oven set forth in claim 1, furthercomprising an air deflector at the top of the open front of the heatingcompartment for deflecting heated air into the heating compartment, saidair deflector being movable between a lowered operative position and araised position.
 15. The oven set forth in claim 14, wherein the airdeflector in its lowered position extends down over only an upperportion of the open front of the heating compartment.
 16. The oven setforth in claim 14, wherein the air deflector comprises a transparentpanel extending across the open front of the heating compartment, and atleast one support for supporting the panel in its lowered operativeposition in which the panel slopes down and forward away from the openfront of the compartment.
 17. An oven for heating food, comprising ahousing having a left side, a right side, a top, a bottom, a back, and afront, an oven cavity inside the housing comprising at least one heatingcompartment for heating food placed in the compartment, the heatingcompartment having a left side wall, a right side wall, a back wall, atop wall, a bottom wall, and an open front, without a door, in opencommunication with a surrounding environment outside the oven, gas flowopenings in at least one of the left and right side walls, a blower forblowing gas through the gas flow openings in at least one of the leftand right side walls into the heating compartment, a heater for heatinggas blowing into the heating compartment through the gas flow openings,and a movable air deflector at the top of the open front of the heatingcompartment for deflecting heated air into the heating compartment, saidair deflector being movable between a lowered operative position and araised position, and said air deflector in its lowered positionextending down over only an upper portion of the open front of theheating compartment.
 18. The oven set forth in claim 17, wherein the airdeflector comprises a panel extending across the open front of theheating compartment, and a mechanism for supporting the panel in itslowered operative position in which the panel slopes down and forwardaway from the open front of the compartment.
 19. An oven for heatingfood, comprising a housing having a left side, a right side, a top, abottom, a back, and a front, an oven cavity inside the housingcomprising at least one heating compartment for heating food placed inthe compartment, the heating compartment having a left side wall, aright side wall, a back wall, and an open front, without a door, in opencommunication with a surrounding environment outside the oven, gas flowopenings in at least one of the left and right side walls, a blower forblowing gas through said gas flow openings in at least one of the leftand right side walls into the heating compartment, a heater for heatinggas blowing into the heating compartment through said gas flow openingsin at least one of the left and right side walls, gas flow openings inthe back wall of the heating compartment, and wherein gas blows into theheating compartment via said gas flow openings in at least one of theleft and right side walls and gas exhausts from the heating compartmentvia said gas flow openings in the back wall of the heating compartment.